1. Field of the Invention
The present invention generally relates to a shifting control system for a clutch-type automatic transmission, specifically, a twin clutch-type automatic transmission. More specifically, the present invention relates to a technology for appropriately carrying out pre-shifting in which a selective meshing mechanism is made to undergo advance shifting that governs implementation of a gear shift stage in one gear shift stage group, while a gear shift stage in another gear shift stage group is engaged.
2. Background Information
When a manual transmission is to be converted to an automatic transmission and a clutch-type automatic transmission is produced, as described in Laid-Open Patent Publication (Kokai) No. 2007-002926, for example, a configuration has been used in which the gear shift stages are separated into a plurality of gear shift stage groups (normally, two gear shift stage groups: an even gear shift stage group and an odd gear shift stage group), and a clutch is provided for each gear shift stage group, so that a rotation can be input to each from a drive mechanism such as an engine. With these types of twin clutch-type automatic transmissions, a condition is produced in which power transmission is possible by the gear shift stage due to the shifting action of the selected meshing mechanism governing implementation of the gear shift stage in a first gear shift stage group, along with engagement of the corresponding clutch. Thus, during implementation of this gear shift stage, with the clutch for the second gear shift stage group in a released state, the selected meshing mechanism that governs implementation of the gear shift stage in the second gear shift stage group (the gear shift stage that is anticipated to be subsequently selected) is made to undergo an advance shifting action (pre-shifting), so that shifting can be carried out only by switching between the two clutches.
In Japanese Laid-Open Patent Publication (Kokai) No. 2007-002926 that relates to this pre-shifting, a shifting control technology for a twin clutch-type automatic transmission is disclosed in which if the release-side clutch in the second gear shift stage group is in a released state, pre-shifting is carried out in the second gear shift stage group, regardless of the engaged state of the engage-side clutch in the first gear shift stage group.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved shifting control system. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.